1. Field of the Invention
The present invention relates to a latch for securing a semiconductor wafer to a clamp ring, weldment or clamp ring for use in a fabrication process.
2. Background Information
Integrated circuits are typically fabricated in a flat circular wafer that is cut from an ingot of semiconductor material. Various lithographic, sputtering, etc. processes are performed on the wafer to create the integrated circuits as is known in the art.
Each wafer is typically secured to a clamp weldment or tab ring of the fabrication equipment by a plurality of latches located about the ring. Each latch may have a roller wheel that is rolled onto the wafer to press the outer wafer edge into the ring. The roller wheel rotates about a horizontal shaft that extends from a latch body. The latch body can swivel about a post that is vertically mounted to the ring. The latch body can be rotated to move the roller wheel between a latched position and an unlatched position.
Because of high temperatures and the migration of material being sputtered onto the wafer it has been found that the roller wheel will drag and stick when the latch is moved to the latched position. This drag increases friction and may create particles that contaminate the wafer. It would be desirable to provide a wafer clamp that minimizes the amount of roller wheel drag and contaminants produced by the clamp.
An embodiment of the present invention may include a latch for securing a wafer to a substrate such as a clamp plate. The latch weldment or tab ring of a wafer holder may include a bearing that allows relative movement between a first element and a second element.